Eojjeoda Guwonhaetjiman, Chaegimeun An Jimnida

After being cast out as a child over suspicions of illegitimacy, Perrianne was adopted by the queen of the neighboring kingdom and has been her loyal spy ever since. She's very happy with her new life when she suddenly hears perplexing news: Duke Exer's long-lost daughter has finally returned... except that's supposed to be her! Tasked with unmasking the imposter posing as herself, she's determined to just get the job done and get out of there. But will her family let her go so easily this time?

(Source: Tapas)